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Noninvasive photoacoustic computed

tomography of mouse brain

metabolism in vivo

Junjie Yao, Jun Xia, Konstantin Maslov, Mohammadreza

R. N. Avanaki, Vassiliy Tsytsarev, et al.

Junjie Yao, Jun Xia, Konstantin Maslov, Mohammadreza R. N. Avanaki,

Vassiliy Tsytsarev, Alexei V. Demchenko, Lihong V. Wang, "Noninvasive

photoacoustic computed tomography of mouse brain metabolism in vivo

," Proc. SPIE 8581, Photons Plus Ultrasound: Imaging and Sensing 2013,

85814A (4 March 2013); doi: 10.1117/12.2005645

Event: SPIE BiOS, 2013, San Francisco, California, United States

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Noninvasive Photoacoustic Comp

uted Tomography of Mouse

Brain Metabolism

In Vivo

Junjie Yao

1

, Jun Xia

1

, Konstantin I. Maslov

1

, Mohammadreza Nasiriavanaki

1

, Vassiliy Tsytsarev

2

,

Alexei V. Demchenko

3

, Lihong V. Wang

1*

1

Optical Imaging Laboratory, Depart

ment of Biomedical Engineeri

ng, Washington University in St.

Louis, St. Louis, MO 63130, USA

2

Department of Anatomy and Neurobiology, Univer

sity of Maryland School of Medicine,

Baltimore, MD 21201, USA

3

Department of Chemistry and Biochemistr

y, University of Missouri-St. Louis,

St. Louis, MO 63121, USA

1

ABSTRACT

To control the overall action of the body, brain consumes a large amount of energy in proportion to its volume.

In

humans and many other species, the brain gets most of its energy from oxygen-dependent metabolism of glucose. An

abnormal metabolic rate of glucose and/or oxygen usually reflects a diseased status of brain, such as cancer or

Alzheimer’s disease. We have demonstrated the feasib

ility of imaging mouse brain metabolism using photoacoustic

computed tomography (PACT), a fast, noninvasive and functi

onal imaging modality with optical contrast and acoustic

resolution. Brain responses to forepaw stimulations were

imaged transdermally and transcranially. 2-NBDG, which

diffuses well across the blood-brain-barrier, provided exogenous contrast for photoacoustic imaging of glucose response.

Concurrently, hemoglobin provided endogenous contrast for

photoacoustic imaging of hemodynamic response. Glucose

and hemodynamic responses were quantitatively unmixed by

using two-wavelength measurements. We found that

glucose uptake and blood perfusion around the somatosensory region of the contralateral hemisphere were both

increased by stimulations, indicating elevated neuron activity. The glucose response amplitude was about half that of the

hemodynamic response. While the glucose response area was more homogenous and confined within the somatosensory

region, the hemodynamic response area showed a clear vascular pattern and spread about twice as wide as that of the

glucose response. The PACT of mouse brain metabolism was validated by high-resolution open-scalp OR-PAM and

fluorescence imaging. Our results demonstrate that 2-NBDG-enhanced PACT is a promising tool for noninvasive studies

of brain metabolism.

Keywords:

Photoacoustic computed tomography, blood flow dynamics, glucose dynamics, functional brain imaging,

glucose metabolism.

1.

INTRODUCTION

In mammals, brain is the function center that coherently c

ontrols the overall action of the body. By performing varied

computation-intensive tasks such as information processing, perception, motor control and learning, brain tissue

consumes a large amount of energy in proportion to its volum

e. It is generally accepted

that energy consumption is

closely coupled with neuron activity: stronger neuron firing, more energy consumption [1]. This relationship has formed

the basis for the functional brain imaging methods, including positron emission tomography (PET), functional magnetic

resonance imaging (fMRI), and near infrared spectroscopy (NIRS), to study brain physiology and pathology [2, 3].

For the first time, we have demonstrated that photoacoustic computed tomography (PACT) is able to image glucose

uptake in the mouse brain, using a newly developed glucose analog 2-NBDG. To demonstrate the metabolic imaging

capability of PACT, we studied

in vivo

forepaw stimulation responses. Our studies showed that PACT could spectrally

*

Corresponding author: Lihong Wang,

lhwang@wustl.edu

. Phone: 1-314-935-6152

Seno Medical Instruments Best Poster Award

Photons Plus Ultrasound: Imaging and Sensing 2013, edited by Alexander A. Oraevsky, Lihong V. Wang,

Proc. of SPIE Vol. 8581 85814A-1

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